Mitigation of radiation-induced oxidative stress by methanolic extract of Tragia involucrata in swiss albino mice

Modulation of radiation-induced intestinal injury by radioprotective agents: a cellular and molecular perspectives

The gastrointestinal (GI) system has rapidly proliferating and differentiating cells, which make it one of the most radiosensitive organs in the body. Exposure to high dose of ionising radiation (IR) during radiotherapy may generate a variety of reactive oxygen species (ROS) and reactive nitrogen species (RNS) including radicals, cause some side effects such as nausea, vomiting, diarrhoea, pain, ulceration, mal-absorption etc. Irradiation disrupts GI system by damaging proliferating stem cells of the crypts that alters the histology and physiology of intestine. Radiation damage reflects the qualitative and quantitative changes in intestinal epithelial stem cells like enterocytes, enteroendocrine cells, goblet cells and Paneth cells. The damaging effects of radiation to bio-molecules and cellular structures can alter gene signalling cascades and grounds genomic instability, protein modifications, cell senescence and cell death. The signalling pathways of GI tract includes Wnt, BMP, Hedgehog, PTEN/PI3K and Notch plays an important role in self-renewal of intestinal stem cells (ISCs) and maintaining the balance between self-renewal and differentiation of ISCs. Various radiation countermeasures including radioprotectors and mitigators are under development phase globally but still not approved for clinical applications during any radiation emergencies. In view of above, present review highlights cellular and molecular interruptions of GI system due to acute and chronic GI radiation injury, role of radioprotectors in signalling cascade modulations in GI epithelium and involvement of ISC markers in radioprotection.

Tragia L. Genus: Ethnopharmacological Use, Phytochemical Composition and Biological Activity

Tragia L. is a genus of plants belonging to the Euphorbiaceae family with worldwide intertropical distribution, composed of more than 150 species. In this literature review, 26 species of the genus used as medicinal plants were found, mainly in East Africa and the Indian subcontinent, with a variety of uses among which antibacterial, anti-inflammatory, anticancer and reproductive health are most common. Research has been done on a few of the species, mostly those of the Old World, with emphasis on four of them: Tragia involucrata Linn., Tragia spathulata Benth., Tragia benthamii Baker and Tragia plukenetii Radcl.-Sm., confirming several ethnomedicinal claims. Moreover, a variety of active phytochemicals have been isolated, mainly ethers, hydrocarbons, flavonoids and sterols. There is ample field for the evaluation of the activity of Tragia extracts and essential oils and the identification of their active compounds, particularly of the New World species, for which there is still very little research.

Radioprotective effect of radiation-induced Lactococcus lactis cell-free extract against 60Coγ injury in mice

Ionizing radiation (IR) is widely used in the diagnosis and treatment of various cancers. However, IR can cause damage to human health by producing reactive oxygen species. Lactococcus lactis is a type of microorganism that is beneficial to human health and has a strong antioxidant capacity. In this study, the protective effect of normal and IR-induced L. lactis IL1403 cell-free extracts (CFE and IR-CFE, respectively) against oxidative damage in vitro and the radioprotective effect of IR-CFE in vivo was evaluated using ⁶⁰Coγ-induced oxidative damage model in mice. Results showed that IR-CFE exhibited a stronger oxidative damage-protective effect than CFE for L. lactis IL1403 under H₂O₂ in vitro. Moreover, IR-CFE also showed strong radioprotective effect on hepatocyte cells (AML-12) under radiation condition, and the effect was better than that of CFE. Animal experiment indicated that IR-CFE could reduce the IR-induced damage to the hematopoietic system by increasing the number of white blood cells and red blood cells in peripheral blood of irradiated mice. It was also observed that IR-CFE could markedly alleviate the ⁶⁰Coγ-induced oxidative stress via increasing the activities of superoxide dismutase and glutathione peroxidase, enhancing the levels of glutathione, and decreasing the contents of malondialdehyde in serum, liver, and spleen. In addition, IR-CFE also could reduce the activities of alanine transaminase and aspartate aminotransferase in serum, thereby reducing radiation damage to the liver. These results suggested that IR-CFE could be considered as potential candidates for natural radioprotective agents. This study provides a theoretical basis for improving the application of lactic acid bacteria.

Radioprotective potential of <italic>Costus afer</italic> against the radiation-induced hematological and histopathological damage in mice

Purpose

This study investigated the possible radioprotective effect of Costus afer extract (CAE) on hematological and histopathological parameters of mice.

Materials and Methods

Fifty-four male mice with mass between 37–43 g, 11–13 weeks old were used for this study. We divided the mice into six different groups containing nine animals, which were then further sub-divided into irradiated groups and un-irradiated groups. Animals received 250 mg/kg body weight extract of CAE by oral gavage for 6 days in addition to feeding and water ad libitum. Animals in the irradiated group were exposed to radiation at the Department of Radiotherapy and Oncology, Grey’s Hospital using a linear accelerator. Blood samples were collected at 48-hour post-irradiation for the hematology test followed by histopathology examination of kidney and liver.

Results

Our findings revealed that 3 Gy and 6 Gy dose of X-ray radiation caused a significant reduction in the white blood cell, packed cell volume, hemoglobin, neutrophils, lymphocytes, eosinophils, and platelet counts compared with the control group. However, the administration of CAE before irradiation significantly increased the mentioned parameters. There was no increase in red blood cell and monocyte among treated groups compared with the control. Histopathological changes in the kidney and liver sections revealed that no visible lesion in the pretreated mice. Hepatocytes seem to be within normal histological limits.

Conclusions

This study concludes that CAE offered some protection against radiation-induced hematological alterations, but there was no significant improvement in the histopathological parameters. Thus, further studies are needed to validate its radioprotective effect on histopathological variables.

Radiomodulatory effect of a non-electrophilic NQO1 inducer identified in a screen of new 6, 8-diiodoquinazolin-4(3H)-ones carrying a sulfonamide moiety

Fifteen new quinazolinone derivatives bearing benzenesulfonamide moiety with variable acetamide tail were synthesized. The structures assigned to the products were concordant with the microanalytical and spectral data. Compounds 4-18 were screened for their ability to induce the antioxidant enzyme NAD(P)H: quinone oxidoreductase 1 (NQO1) in cells, a classical target for transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2). The 2-((6,8-diiodo-4-oxo-3-(4-sulfamoylphenyl)-3,4-dihydroquinazolin-2-yl)thio)-N-(3,4,5-trimethoxyphenyl) acetamide 15 showed the most potent NQO1 inducer activity in vitro. Compound 15 had low toxicity in mice (LD50 = 500 mg/kg). It also reduced the damaging effects of gamma radiation, as assessed by the levels of Nrf2, NQO1, reactive oxygen species (ROS) and malondialdehyde (MDA) in liver tissues. In addition, compound 15 showed amelioration in the complete blood count of irradiated mice and enhanced survival over a period of 30 days following irradiation. Molecular docking of 15 inside the Nrf2-binding site of Kelch-like ECH associated protein 1 (Keap1), the main negative regulator of Nrf2, showed the same binding interactions as that of the co-crystallized ligand considering the binding possibilities and energy scores. These findings suggest that compound 15 could be considered as a promising antioxidant and radiomodulatory agent.